2.5V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK II JR.
INDUSTRIAL TEMPERATURE RANGE
2.5V PROGRAMMABLE
SKEW PLL CLOCK DRIVER
TURBOCLOCK™ II JR.
FEATURES:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Ref input is 3.3V tolerant
4 pairs of programmable skew outputs
Low skew: 185ps same pair, 250ps all outputs
Selectable positive or negative edge synchronization:
Excellent for DSP applications
Synchronous output enable
Input frequency:
– Std: 6MHz to 160MHz
– A: 6MHz to 200MHz
Output frequency:
– Std: 6MHz to 160MHz
– A: 6MHz to 200MHz
2x, 4x, 1/2, and 1/4 outputs
3-level inputs for skew and PLL range control
PLL bypass for DC testing
External feedback, internal loop filter
12mA balanced drive outputs
Low Jitter: <100ps cycle-to-cycle
Standard and A speed grades
Available in TQFP package
IDT5T9950/A
DESCRIPTION:
The IDT5T9950 is a high fanout 2.5V PLL based clock driver intended
for high performance computing and data-communications applications. A
key feature of the programmable skew is the ability of outputs to lead or lag
the REF input signal. The IDT5T9950 has eight programmable skew
outputs in four banks of 2. Skew is controlled by 3-level input signals that
may be hard-wired to appropriate high-mid-low levels.
When the
sOE
pin is held low, all the outputs are synchronously enabled.
However, if
sOE
is held high, all the outputs except 2Q0 and 2Q1 are
synchronously disabled. The LOCK output asserts to indicate when Phase
Lock has been achieved.
Furthermore, when PE is held high, all the outputs are synchronized with
the positive edge of the REF clock input. When PE is held low, all the outputs
are synchronized with the negative edge of REF. The IDT5T9950 has
LVTTL outputs with 12mA balanced drive outputs.
FUNCTIONAL BLOCK DIAGRAM
sO E
Skew
Select
3
3
1F1:0
PE TEST
Skew
Select
3
PLL
FB
3
FS
3F1:0
Skew
Select
3
3
3
2F1:0
1Q
0
1Q
1
2Q
0
2Q
1
3
REF
3Q
0
3Q
1
Skew
Select
3
3
4F1:0
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
4Q
0
4Q
1
INDUSTRIAL TEMPERATURE RANGE
1
c
2002
Integrated Device Technology, Inc.
FEBRUARY 2002
DSC 5869/5
IDT5T9950/A
2.5V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK II JR.
INDUSTRIAL TEMPERATURE RANGE
PIN CONFIGURATION
GND
TEST
REF
3F
0
V
DD
2F
1
2F
0
FS
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
DDQ
, V
DD
V
I
Description
Supply Voltage to Ground
DC Input Voltage
REF Input Voltage
Maximum Power
24
23
22
21
20
19
18
17
1F
1
1F
0
sOE
V
D DQ
1Q
0
1Q
1
GND
GND
Max
–0.5 to +4.6
–0.5 to V
DD
+0.5
–0.5 to +4.6
T
A
= 85°C
T
A
= 55°C
0.7
1.1
–65 to +150
Unit
V
V
V
W
°C
32
3F
1
4F
0
4F
1
PE
V
D DQ
4Q
1
4Q
0
GND
1
2
3
4
5
6
7
8
9
31
30
29
28
27
26
25
Dissipation
T
STG
Storage Temperature Range
NOTE:
1. Stresses beyond those listed under ABSOLUTE MAXIMUM RATINGS may cause
permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolute-
maximum-rated conditions for extended periods may affect device reliability.
CAPACITANCE
(T
A
= +25°C, f = 1MHz, V
IN
= 0V)
Parameter
C
IN
Description
Input Capacitance
Typ.
5
Max.
7
Unit
pF
10
11
12
13
14
15
16
V
D DQ
V
D DQ
3Q
1
3Q
0
2Q
1
GND
TQFP
TOP VIEW
PIN DESCRIPTION
Pin Name
REF
FB
TEST
(1)
sOE
(1)
Type
IN
IN
IN
IN
Description
Reference Clock Input
Feedback Input
When MID or HIGH, disables PLL (except for conditions of Note 1). REF goes to all outputs. Skew Selections (See Control Summary
Table) remain in effect. Set LOW for normal operation.
Synchronous Output Enable. When HIGH, it stops clock outputs (except 2Q
0
and 2Q
1
) in a LOW state (for PE = H) - 2Q
0
and 2Q
1
may
be used as the feedback signal to maintain phase lock. When TEST is held at MID level and
sOE
is HIGH, the nF[
1:0
] pins act as output
disable controls for individual banks when nF[
1:0
] = LL. Set
sOE
LOW for normal operation (has internal pull-down).
Selectable positive or negative edge control. When LOW/HIGH the outputs are synchronized with the negative/positive edge of the reference
clock (has internal pull-up).
nF
[1:0]
FS
nQ
[1:0]
V
DDQ
V
DD
GND
IN
IN
OUT
PWR
PWR
PWR
3-level inputs for selecting 1 of 9 skew taps or frequency functions
Selects appropriate oscillator circuit based on anticipated frequency range. (See Programmable Skew Range.)
Four banks of two outputs with programmable skew
Power supply for output buffers
Power supply for phase locked loop, lock output, and other internal circuitry
Ground
PE
IN
NOTE:
1. When TEST = MID and
sOE
= HIGH, PLL remains active with nF[
1:0
] = LL functioning as an output disable control for individual output banks. Skew selections remain in
effect unless nF[
1:0
] = LL.
2Q
0
NOTE:
1. Capacitance applies to all inputs except TEST, FS, nF
[1:0]
, and DS
[1:0]
.
FB
2
IDT5T9950/A
2.5V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK II JR.
INDUSTRIAL TEMPERATURE RANGE
PROGRAMMABLE SKEW
Output skew with respect to the REF input is adjustable to compensate
for PCB trace delays, backplane propagation delays or to accommodate
requirements for special timing relationships between clocked compo-
nents. Skew is selectable as a multiple of a time unit (t
U
) which ranges
from 782ps to 1.5625ns for Standard version and 6.25ps to 1.3ns for A
version (see Programmable Skew Range and Resolution Table). There
are nine skew configurations available for each output pair. These con-
figurations are chosen by the nF
1:0
control pins. In order to minimize the
number of control pins, 3-level inputs (HIGH-MID-LOW) are used, they
are intended for but not restricted to hard-wiring. Undriven 3-level in-
puts default to the MID level. Where programmable skew is not a re-
quirement, the control pins can be left open for the zero skew default
setting. The Control Summary Table shows how to select specific skew
taps by using the nF
1:0
control pins.
EXTERNAL FEEDBACK
By providing external feedback, the IDT5T9950 gives users flexibility
with regard to skew adjustment. The FB signal is compared with the
input REF signal at the phase detector in order to drive the VCO. Phase
differences cause the VCO of the PLL to adjust upwards or downwards
accordingly.
An internal loop filter moderates the response of the VCO to the
phase detector. The loop filter transfer function has been chosen to
provide minimal jitter (or frequency variation) while still providing accu-
rate responses to input frequency changes.
PROGRAMMABLE SKEW RANGE AND RESOLUTION TABLE
FS = LOW
Timing Unit Calculation (t
U
)
VCO Frequency Range (F
NOM
)
(1,2)
Skew Adjustment Range
(3)
Max Adjustment:
±7.8125ns
±67.5°
±18.75%
Example 1, F
NOM
= 25MHz
Example 2, F
NOM
= 37.5MHz
Example 3, F
NOM
= 50MHz
Example 4, F
NOM
= 75MHz
Example 5, F
NOM
= 100MHz
Example 6, F
NOM
= 150MHz
Example 7, F
NOM
= 200MHz
t
U
= 1.25ns
t
U
= 0.833ns
—
—
—
—
—
±9.375ns
±135°
±37.5%
—
—
t
U
= 1.25ns
t
U
= 0.833ns
—
—
—
±9.375ns
±270°
±75%
—
—
—
—
t
U
= 1.25ns
t
U
= 0.833ns
—
±7.8125ns
±67.5°
±18.75%
t
U
= 1.25ns
t
U
= 0.833ns
t
U
= 0.625ns
—
—
—
—
±7.8125ns
±135°
±37.5%
—
—
t
U
= 1.25ns
t
U
= 0.833ns
t
U
= 0.625ns
—
—
±7.8125ns
±270°
±75%
—
—
—
—
t
U
= 1.25ns
t
U
= 0.833ns
t
U
= 0.625ns
ns
Phase Degrees
% of Cycle Time
1/(32 x F
NOM
)
24 to 40MHz
IDT5T9950
FS = MID
1/(16 x F
NOM
)
40 to 80MHz
FS = HIGH
1/(8 x F
NOM
)
80 to 160MHz
FS = LOW
IDT5T9950A
FS = MID
FS = HIGH
1/(8 x F
NOM
)
96 to 200MHz
Comments
1/(32 x F
NOM
) 1/(16 x F
NOM
)
24 to 50MHz 48 to 100MHz
NOTES:
1. The device may be operated outside recommended frequency ranges without damage, but functional operation is not guaranteed.
2. The level to be set on FS is determined by the nominal operating frequency of the VCO and Time Unit Generator. The VCO frequency always appears at 1Q
1:0
, 2Q
1:0
, and
the higher outputs when they are operated in their undivided modes. The frequency appearing at the REF and FB inputs will be the same as the VCO when the output connected
to FB is undivided. The frequency of the REF and FB inputs will be 1/2 or 1/4 the VCO frequency when the part is configured for frequency multiplication by using a divided
output as the FB input.
3. Skew adjustment range assumes that a zero skew output is used for feedback. If a skewed Q output is used for feedback, then adjustment range will be greater. For example
if a 4t
U
skewed output is used for feedback, all other outputs will be skewed –4t
U
in addition to whatever skew value is programmed for those outputs. ‘Max adjustment’ range
applies to output pairs 3 and 4 where ± 6t
U
skew adjustment is possible and at the lowest F
NOM
value.
3
IDT5T9950/A
2.5V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK II JR.
INDUSTRIAL TEMPERATURE RANGE
CONTROL SUMMARY TABLE FOR FEEDBACK SIGNALS
nF1:0
LL
(1)
LM
LH
ML
MM
MH
HL
HM
HH
Skew (Pair #1, #2)
–4t
U
–3t
U
–2t
U
–1t
U
Zero Skew
1t
U
2t
U
3t
U
4t
U
Skew (Pair #3)
Divide by 2
–6t
U
–4t
U
–2t
U
Zero Skew
2t
U
4t
U
6t
U
Divide by 4
Skew (Pair #4)
Divide by 2
–6t
U
–4t
U
–2t
U
Zero Skew
2t
U
4t
U
6t
U
Inverted
(2)
NOTES:
1. LL disables outputs if TEST = MID and
sOE
= HIGH.
2. When pair #4 is set to HH (inverted),
sOE
disables pair #4 HIGH when PE = HIGH,
sOE
disables pair #4 LOW when PE = LOW.
RECOMMENDED OPERATING RANGE
Symbol
V
DD
/V
DDQ
T
A
Description
Power Supply Voltage
Ambient Operating Temperature
Min.
2.3
-40
Typ.
2.5
+25
Max.
2.7
+85
Unit
V
°C
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Symbol
V
IH
V
IL
V
IHH
V
IMM
V
ILL
I
IN
Parameter
Input HIGH Voltage
Input LOW Voltage
Input HIGH Voltage
(1)
Input MID Voltage
(1)
Input LOW Voltage
(1)
Input Leakage Current
(REF, FB Inputs Only)
I
3
I
PU
I
PD
V
OH
V
OL
3-Level Input DC Current (TEST, FS, nF
[1:0]
)
Input Pull-Up Current (PE)
Input Pull-Down Current (sOE)
Output HIGH Voltage
Output LOW Voltage
Conditions
Guaranteed Logic HIGH (REF, FB Inputs Only)
Guaranteed Logic LOW (REF, FB Inputs Only)
3-Level Inputs Only
3-Level Inputs Only
3-Level Inputs Only
V
IN
= V
DD
or GND
V
DD
= Max.
V
IN
= V
DD
V
IN
= V
DD
/2
V
IN
= GND
V
DD
= Max., V
IN
= GND
V
DD
= Max., V
IN
= V
DD
V
DD
= Min., I
OH
=
−
12mA
V
DD
= Min., I
OL
= 12mA
HIGH Level
MID Level
LOW Level
—
+200
+50
—
—
+100
—
0.4
µA
µA
V
V
µA
Min.
1.7
—
V
DD
/2
−
0.2
—
V
DD
−
0.4
Max.
—
0.7
—
V
DD
/2+0.2
0.4
+5
Unit
V
V
V
V
V
µA
−
5
−
50
−
200
−
100
—
2
—
NOTE:
1. These inputs are normally wired to V
DD
, GND, or unconnected. Internal termination resistors bias unconnected inputs to V
DD
/2. If these inputs are switched, the function and
timing of the outputs may be glitched, and the PLL may require an additional t
LOCK
time before all datasheet limits are achieved.
4
IDT5T9950/A
2.5V PROGRAMMABLE SKEW PLL CLOCK DRIVER TURBOCLOCK II JR.
INDUSTRIAL TEMPERATURE RANGE
POWER SUPPLY CHARACTERISTICS
5T9950
Symbol
I
DDQ
Parameter
Quiescent Power Supply Current
Test Conditions
(1)
V
DD
= Max., TEST = MID, REF = LOW,
PE = LOW,
sOE
= LOW, FS = MID
All outputs unloaded
∆I
DD
Power Supply Current per Input HIGH
(REF and FB inputs only)
FS = L
I
DDD
Dynamic Power Supply Current per Output
FS = M
FS = H
FS = L
I
TOT
Total Power Supply Current
FS = M
FS = H
NOTES:
1. Measurements are for divide-by-1 outputs and nF
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